Sparger devices are commonly used for introducing a fluid flow, such as an airflow, a mixture of air and another gas, a mixture of gas and a water flow, a mixture of air and a water flow or any combination thereof, into slurry in such a manner that bubbles and/or froth is generated.
For a sparger device to operate properly, it is important that no impurities are introduced into the sparger device, particularly a nozzle opening thereof, as any impurities could hinder the flow of the sparging fluid or otherwise result in reduced operational capabilities. This is particularly prominent in flotation applications, where the slurry to be sparger contains solids in the form of mineral particles.
During normal operation, the flow of the sparging fluid itself prevents slurry backflow via the nozzle opening of the sparger device. However, if the flow of the sparging fluid is interrupted the fluid pressure of the slurry, namely hydrostatic pressure within the slurry tank, induces a slurry backflow via the nozzle opening unless this is somehow prevented.
Document CN 201231183 Y discloses a sparger device, in which a biasing spring is used to bias a needle against a nozzle opening. U.S. Pat. No. 5,139,663 a discloses a discharge valve for a flotation system, which discharge valve is actuated by a piston member coupled to a cap for opening or closing a discharge opening. U.S. Pat. No. 3,410,518 a discloses a self-closing valve arrangement.